Evolved Node B's (eNBs) providing User Equipments (UEs) with an access service are connected with each other, and an eNB is connected with a core network node, in a wired manner in a Long Term Evolution (LTE) system. The eNBs exchange information with each other via an X2 interface. Since there is a long delay generally at the order of 20 ms via the X2 interface, the information exchanged between the eNBs via the X2 interface are generally semi-static information, and since dynamic information can not be exchanged between the eNBs, the eNBs can not dynamically interoperate in coordination.
In order to improve the transmission rate of data, and the throughput of a cell, a Relay Node (RN) is introduced to the LTE system. The RN accesses a core network through a donor evolved Node B (DeNB), and there is no direct wired interface between the RN and the core network node; and in this architecture, a User Equipment (UE) communicates with the RN via a radio interface Uu. and the RN can communicate with the DeNB via a radio interface Un, as illustrated in FIG. 1. In order to transmit downlink data between the RN and the DeNB, the DeNB firstly needs to transmit control signaling, which includes information of downlink scheduling of the RN, to the RN, and then can transmit the downlink data; and alike in order to transmit uplink data between the RN and the DeNB, the RN firstly needs to transmit an uplink transmission request to the DeNB, and can transmit the uplink data after being provided with an uplink transmission resource.
In an ultra-dense network, there is a large intersection between coverage areas of different eNBs, and the distance between eNBs is short, thus making it possible to establish a radio interface between the eNBs. In a scenario where access points are deployed ultra-densely, if the eNBs can interact with each other via a radio interface, then the delay may be well shortened as compared with the existing X2 interface to thereby improve the efficiency of exchanging information between the eNBs.
In order to transmit information between the eNBs via an air interface, the transmission procedures above between the RN and the DeNB via an air interface can be applied. However, the coordination is not limited to two eNBs, in general, resources to be occupied, and data to be transmitted need to coordinated between adjacent eNBs, so when the transmission procedures above between the RN and the DeNB via an air interface are applied, then every two eNBs may interact with each other, for example, if an eNB1, an eNB2, and an eNB3 coordinate with each other, then information may be exchanged respectively between the eNB1 and the eNB2, and between the eNB1 and the eNB3, and between the eNB2 and the eNB3.
Obviously the interaction mode above is so inefficient that may seriously discourage the eNBs and other access points from interoperating in coordination.